1. Field of the Invention
The present invention relates to a method of displaying character data in a digital television broadcasting receiver.
2. Description of the Prior Art
In recent years, television broadcasting has been digitized. In BS digital broadcasting which is scheduled to start at the end of this year, it is possible to broadcast, in addition to images (SD; Standard Definition) having a conventional resolution, size, and aspect ratio (4:3), images (HD; High Definition) having a higher resolution and having a different size and aspect ratio (16:9) on the same channel.
Therefore, digital television broadcasting receivers have the function of correcting images which differ in resolution proportionally depending on the aspect ratio of a monitor in the receiver and displaying the corrected images.
In the digital broadcasting, not only an image but also character data to be displayed over the image, for example, subtitles is fed with the character data multiplexed on the image. The digital broadcasting receiver has the function of analyzing the fed character data and displaying characters with the characters overlapped with the image at a designated position in a designated size and a designated color.
In the digital broadcasting, images having different aspect ratios are fed. Accordingly, the display size and the display position of character data to be overlapped with the image are also fed as a display size and a display position which use as a basis a display range corresponding to the aspect ratio of the image. On the other hand, the aspect ratio of the monitor in the receiver is fixed. When the image having an aspect ratio different from the aspect ratio of the monitor is received on the side of the receiver, therefore, the image must be corrected such that the aspect ratio thereof is adaptable to the aspect ratio of the monitor, and the character data must be similarly corrected.
When the characters are enlarged or reduced similarly to the image, however, the characters are crushed and are difficult to read. Further, when the characters are enlarged or reduced similarly to the image, on-screen displays respectively corresponding to the aspect ratios of all the images are required.
In order to avoid this, a font corresponding to the character size after the correction may be used. In the case, however, font data in a lot of sizes must be stored in a memory.
An object of the present invention is to provide a method of displaying character data in a digital television broadcasting receiver capable of displaying characters over an image having an aspect ratio different from the aspect ratio of a monitor in the receiver using only an on-screen display corresponding to the aspect ratio of the monitor.
In a method of displaying character data in a digital television broadcasting receiver in a case where the aspect ratio of a monitor differs from the aspect ratio of a received image, the method according to the present invention is characterized by comprising the steps of correcting, with respect to the size of characters, the size designated by the character data proportionally depending on the aspect ratio of the image and the aspect ratio of the monitor, and selecting, out of the sizes of fonts of the receiver, the size which is not more than and is closest to the corrected size; and correcting, with respect to the display position of the characters, the display position designated by the character data proportionally depending on the aspect ratio of the image and the aspect ratio of the monitor.
It is preferable that the display position is corrected, with respect to a string of characters to be continuously displayed in the character data, only with respect to the character at the head of the character string, and the display position is moved by an amount of movement corresponding to character spacing previously determined depending on the selected character size with respect to the character subsequent to the character at the head.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.